An 85-year-old Oregon woman says a prominent Manhattan art gallery doctored authenticity documents to dupe her into overpaying for 90 Andy Warhol prints– and now she’s suing the Lower East Side dealers to find out if she was fleeced on another 50 pieces by modern masters like Pablo Picasso and Keith Haring.

Nira Levine, a retired psychologist from Forest Grove, Oregon, first invested in artwork with John and Kristine Woodward of the Woodward Gallery on Eldridge Street in 2002.

Levine says in her Manhattan Supreme Court lawsuit that she paid the Woodwards nearly $1 million over the years for paintings including Picasso’s “Green Hair Woman” and Haring’s “Subway.” She purchased the pieces with her own funds or co-owned them with the Woodwards, her suit says.

The Woodwards then resold the art through their gallery and split the proceeds 50-50 with Levine.

But when Levine learned in 2014 that the couple allegedly overcharged her for etchings, she grew suspicious.

So Levine asked Kristine Woodward for sales receipts related to 90 still lifes from Warhol’s “Spacefruit” series that the gallery supposedly bought for $180,000 in 2008. Levine had paid the Woodwards $90,000 for her 50 percent interest in the collection.

In a 2014 email Kristine Woodward admits that “there is no invoice” because her husband, a prominent dealer who was curator at the recently-shuttered Four Seasons Restaurant, acquired them from Warhol’s printer, who died in 2001.

A restorer confirmed Levine’s suspicions that the Woodwards invented the 2008 transaction so they could bilk her out of $90,000, the suit claims.

Levine admits she never saw the artwork or related documentation herself because she trusted the Woodwards.

She now worries that she was defrauded on another 50 works she bought through the gallery. She’s suing for access to paperwork related to the purchases.

Kristine Woodward declined to comment on the specifics of the allegations but said the suit “has no merit.”

“The gallery has continued to have in integrity in all that we do in the last 23 years,” she said.